1. Field of the Invention
The invention relates to a nail locating device with a pivotable magnet supporting indicator rod to permit location of a magnetically attractive nail on a non-magnetically attractive board in a fast and convenient manner.
2. Description of the Related Art
A nail locating device is used for locating a nail that was driven into a board when removing the nail from the latter. Boards used for decorating a building interior or a room place are sometimes covered with wallpaper or coated with paint such that the nails driven into the same cannot be found easily. When the boards are to be dismantled, the nails driven thereinto should be removed, and a nail locating device is thus required.
A conventional nail locating device for locating a magnetically attractive nail that was driven into a non-magnetically attractive board generally includes a transparent casing made of plastic and provided with a pivot shaft, and an indicator rod disposed within the casing and having an upper end pivoted to the pivot shaft about a pivot axis. The indicator rod has a bottom end provided with a magnet. The casing has front and rear sides provided with aligned marks that are aligned vertically with the pivot shaft.
When the conventional nail locating device is used to locate an iron nail that was driven into a wooden board, the casing is moved on a surface of the board so that the indicator rod pivots in the casing in the direction of the nail due to attraction of the magnet to the nail. The casing is moved by the operator until the indicator rod is generally perpendicular to the wooden board, indicating that the nail is located on a line that passes through the aligned marks. A first indicating line along the aligned marks is then drawn on the board by the operator. Thereafter, the casing is once again moved on the surface of the board, and the aforementioned procedure is repeated until a second indicating line is obtained. The first and second indicating lines intersect at a point, which is the location of the nail.
Although the conventional nail locating device achieves the purpose of locating a magnetically attractive nail, such as an iron nail, on a non-magnetically attractive board, such as a wooden board, it suffers from the following drawback: Two line drawing operations must be performed so as to draw two intersecting indicating lines before the nail can be located, thereby resulting in a relatively inconvenient and time-consuming locating operation.
In co-pending U.S. patent application Ser. No. 09/048,892, filed by the applicant on Mar. 27, 1998, there is disclosed a nail locating device with a magnet supporting indicator rod mounted in a ball socket. The nail locating device includes a seat adapted to be moved on a surface of a non-magnetically attractive board and having open upper and lower end portions, and an intermediate portion between the upper and lower end portions and formed with the ball socket therein. A coupling member has a ball portion hinged to the seat in the ball socket. The indicator rod is received in the seat, and extends from the upper end portion, through the ball portion of the coupling member, and into the lower end portion of the seat. The indicator rod has a bottom end provided with a magnet that is adapted to be attracted to a magnetically attractive nail that was driven into the board such that the indicator rod pivots in the seat due to attraction of the magnet to the nail in order to indicate the location of the nail in the board.
The coupling member further includes a tubular sleeve portion extending downwardly from the ball portion and sleeved on the indicating rod. The bottom end of the indicator rod has the head portion of a pressing nail mounted thereon below the magnet. The pressing nail further has a tip that projects downwardly and outwardly of the sleeve portion. The indicator rod has a top end which projects outwardly and upwardly of the upper end portion of the seat to permit pressing of the indicator rod so that the pressing nail can make a mark after the nail is located. The sleeve portion has a bottom end formed with a plurality of spring leaves that extend radially and inwardly therefrom and that have upturned distal ends abutting against the head portion of the pressing nail for biasing the indicator rod upwardly.
Some of the drawbacks of the nail locating device disclosed in the aforesaid co-pending U.S. patent application are as follows:
1. A separate component, i.e. the coupling member, is required to mount the indicator rod in the seat.
2. The seat has an annular surrounding wall that is provided with at least one axial slit so as to impart resilience thereto in order to permit forcing of the ball portion of the coupling member into the ball socket via the upper end portion of the seat. In addition, the spring leaves are formed at the bottom end of the sleeve portion of the coupling member. The components of the nail locating device are difficult to form, thereby resulting in higher production costs.
3. While the pressing nail can be used to make a mark after a nail is located, it is noted that the mark is not clearly visible when the nail is made of a relatively hard material.
Therefore, the main object of the present invention is to provide a nail locating device with a pivotable magnet supporting indicator rod to permit location of a magnetically attractive nail on a non-magnetically attractive board in a fast and convenient manner.
Another object of the present invention is to provide a nail locating device of the aforesaid type having components that are relatively easy to manufacture and assemble, and that facilitate making of a visible indication when the location of a nail driven into a board is found.
According to the present invention, a nail locating device is adapted for locating a magnetically attractive nail that was driven into a non-magnetically attractive board, and comprises a seat, an indicator rod, and a biasing spring.
The seat is adapted to be moved on a surface of the board, and confines a vertically extending receiving space therein.
The indicator rod is disposed in the receiving space, and has a ball portion and a magnet supporting portion that extends downwardly from the ball portion. The magnet supporting portion has a magnet member mounted thereto.
The biasing spring is disposed in the receiving space, and supports the ball portion of the indicator rod in the receiving space such that the indicator rod is pivotable in the seat and is movable downwardly in the receiving space due to attraction of the magnet member to the nail in order to indicate the location of the nail in the board.